Data Types in java programming with example

Data Types in Java

In java, there are two types of data types ·   primitive data types ·    non-primitive data types

                  

Primitive  Data Types:

There are eight primitive data type supported by Java.Primitive data types are predefined by the language and named by keyword.Let us look into detail about the eight primitive data types.

 byte:

 Byte data type is an 8-bit signed two's complement integer.

  • Minimum value is -128 (-2^7)

  • Maximum value is 127 (inclusive)(2^7 -1)

  • Default value is 0

  • Byte data type is used to save space

  • Example: byte a = 100, byte b = -50 short

             

 short:

 Short data type is a 16-bit signed two's complement integer.

· Minimum value is -32,768 (-2^15)

· Maximum value is 32,767(inclusive) (2^15 -1) 

· Short data type can also be used to save memory as byte data type.

· Default value is 0. • Example: short s= 10000, short r = -20

int:    

· int data type is a 32-bit signed two's complement integer.

· Minimum value is - 2,147,483,648.(-2^31)

· Maximum value is 2,147,483,647(inclusive).(2^31 -1)

· Int is generally used as the default data type for integral values unless there is a             concern about memory.

· The default value is 0.

·  Example: int a = 100000, int b = -200000

long:

· Long data type is a 64-bit signed two's complement integer.

· Minimum value is -9,223,372,036,854,775,808.(-2^63)

· Maximum value is 9,223,372,036,854,775,807 (inclusive). (2^63 -1)

· This type is used when a wider range than int is needed.

· Default value is 0L.

· Example: int a = 100000L, int b = -200000L

float:  

· Float data type is a single-precision 32-bit IEEE 754 floating point.

· Float is mainly used to save memory in large arrays of floating point numbers.

· Default value is 0.0f.

· Float data type is never used for precise values such as currency.

· Example: float f1 = 234.5f 

double:               

· double data type is a double-precision 64-bit IEEE 754 floating point.

· This data type is generally used as the default data type for decimal values

·  Double data type should never be used for precise values such as currency.

·  Default value is 0.0d.

·  Example: double d1 = 123.4          

boolean:

· boolean data type represents one bit of information.

· There are only two possible values: true and false.

· This data type is used for simple flags that track true/false conditions.

· Default value is false.

· Example: boolean one = true

Char:

char data type is a single 16-bit Unicode character.

· Minimum value is '\u0000' (or 0).

· Maximum value is '\uffff' (or 65,535 inclusive).

· Char data type is used to store any character. •

· Example: char letterA ='A'

Reference  Data Types:        

Reference variables are created using defined constructors of the classes. They are used to access objects. These variables are declared to be of a specific type that cannot be changed. For example, Employee, Rectangle, etc.  Class objects and various types of array variables come under reference data type.  Default value of any reference variable is null. A reference variable can be used to refer to any object of the declared type or any compatible type.

Predefined Reference Types are:

1.       String

2.       Object